Heat exchanger



Jan. 27 1942. 2,270,864

EMIL'IEN BLAIS, COMMONLY KNOWN As EMILE BLAIR HEAT EXCHANGER Filed June 6, 1938 4 Sheets-Sheet 1 ATTORNEY Jan. 27, 1942. 2,270,864

EMlLlEN BLAIS,,COMMONLY KNOWN AS EMILE BLAIR- HEA'I' EXCHANGER 4 Sheets-Sheet 3 Filed June 6, 1938 odooooooeooooooooooo UOOOOOOOOOOOOOOOOOOO OOOOOOOOOOOOOOOOOOOO OOOOOOOOOOOOGOOOOOOO QOOOOOOOOOOOOOOOOOOO OOOOOOOOOOOOOOOOOOOO UGOOA UOOOOOOOOOGOOOOG .OOOOOOOOOOQOOOOOOOOO OOOOGOOOOGOOOOOOOOOO O OQOOOOQOOOOGOOOOGOO UOOOOOOOOOOQOOOOOOOO GGOOOOOQOOOOOOOOOOOO OOOOOOOOOOOOGOOOOGOO OOOOOOOOOOOOOOOOOOOO OOOOOOGOOOO OOOOOOOO OOOOOOOOOOOOOOOOOOOO A INVENTOR o o o o o o o o o o o o o o 0 0 0 0 0 0 0 0 0 o o o o o o o o o o o o o omowo o omow OMVOOOQOOOOOGOOOOOOOO a M ATTORNEY Jan. 27, 1942.

EMILIEN BLAIS, COMMONLY KNOWN As EMILE BLAIR HEAT EXCHANGER 4 Sheets-Sheet 4 Filed June 6, 1938 A I 6/ f i 1 69 I If i! In w I62 WW INVENTO I ATTORNEY Patented Jan. 27,, E942 m wi h t. t r S fiat a at r1..- hi it Us in.

$5,2iiifiiiid HEAT Emilien Blaia, commonly Blair, New Haven, (3cm, assignor, by means merits, to Western Gozmpany, cor

aeration of Delaware hppllcationllune 6,1935% Serial No. filiifiw iii-ii Great Britain May 21%, 1938 This invention relates generally to heat ex-=- apart to provide a space for the passage of another fluid around the tubes. In constructing heat exchangers oi the type to which the present invention relates, it is desirable that the tubes be connected to term the core in such a manner that they will be permanently and securely fastened together, the ends of the core will be completely sealed around the tubes, and the bondbetween the tubes will be resistant to heat, corrosion, vibration and other destructive effects. Ordinary solder is unsuited for this use becauseit does not have sumoient mechanical strength and, for many uses, does not have a sumciently high melting point. Certain fusible metallic bonding materials have the desired properties but require the application of so much heat to fuse them, that the tubes are so annealed or softened as not to have the desired rigidity and resistance to deformation.

In accordance with the present invention, a plurality of thin wall tubes of suitable shape and material are assembled into substantially the shape of the core to be formed and a. fusible metallic bonding material of relatively high me chanical strength and relatively'high melting point is applied to the end portions of the tubes to secure them together and to provide a seal around the tube ends. The tubes are spaced at least at their body portions to provide space for one of the fluids. This is accomplished by expanding the ends of the tubes, or by providing additional spacing members between rows of tubes or by inserting the tubes in spaced openwith to absorb or dissipate sufficient of the heat of bonding to prevent annealing of the tubes.

In certain cases, as for example, where a large original arrangements and combinations of steps number of tubes'are assembled, a greater heat tubes.

Imperforate, preferably corrugated, side plates, which also reinforce the core, and ducts or tanks or" suitable construction are assembled with the core, and are joined thereto by a bonding operation preferably similar to that employed in join ing the tubes.

The invention also provides a novel heat exchanger core wherein the tubes are firmly and rigidly secured together and the spaces betweenthe tube ends are positively sealed. ihe bushings or ferrules serve to strengthen and reinforce the ends of the core. Where the tubes are assembled without end header plates, the bushings, together with the tube ends and bonding materiai and spacing strips when these are usedconstitute a rigidsealing end wall around the ends of the tubes. These end walls, together with the reinforcing side walls, provide a strong, rigid core construction.

an object of the present invention is the provision of a method for assembling heat exchanger cores from tubes wherein the tubes are secured in the core by a relatively high melting point bonding material, without annealing or softening the tubes.

Another object of the invention is the provision of a heat exchanger core of the tube type wherein the tubes are secured together at their ends without a header plate, and individual reinforcing members are provided which form, together with the tube ends and bonding material, a rigid sealing end wall.

Another object of the invention is to provide a. heat exchanger having a core of the type constituted by a plurality of tubes, in which heat exchanger, the several parts are secured together by a bond of high mechanical strength.

Another object of. the present invention is the provision of a heat exchanger core of the tube type having a novel reinforcing side and end wall construction.

The invention further consists in the new and novel features of operation and the new and in the process hereinafter described and'more particularly set forth in the claims.

The invention also consists in forming a prodnot having the general characteristics, the new and useful applications, and the several original features of utility hereinafter set forth and claimed.

Other features, objects and advantages of the present invention will in part be pointed out and inpartbecome apparent inconnection with the following detailed description of certain i1lustrative forms of construction; reference being had to the accompanying drawings, wherein Fig. 6 is a top plan view of an assembly frame suitable for use in assembling the tubes and spacing strips, which view shows two spacing strips and two tubes in position in theframe;

Fig. 7 is a fragmentary, enlarged cross-sec-- tional view taken along line 1-4 of Fig. 6;

Fig. 8 is a perspective view showing an assembly comprising a pair 'of spacing strips and tubes;

Fig. 9 is a front elevational view of a clamp suitable for use in maintaining the tubes in assembled relation forbonding, the view showing a number of tubes and assemblies in the frame;

Fig. 10 is an enlarged fragmentary cross-sectional view taken along line |l0 of Fig. 9 and illustrating particularly one of the heat dissipating rods within one of the tubes, the assembled aeraeea tility to permit the necessary working, suficient resistance to rust and corrosion, sumcientmechanical strength, and the like.

In accordance with an illustrative embodiment of the invention, a tube I (Fig. 1) is provided having an elongated cylindrical body 2 and enlarged cylindrical ends 3. The tube may be formed in any suitable manner, but it is important that the metal be sufliciently hard and rigid to resist undesired defamation. Preferably, the tube is formed by extruding a blank of metal into a cylinder, trimming the cylinder to the proper length, straightening the cylinder, when necessary, and expanding the ends of the cylinder.

Preferably, any adherent foreign matter is removed from the tube; after forming, by means of a bright-dip which consists in immersing the tube in a suitable cleansing material, as for example, one containing equal parts of commercial nitric and sulphuric acids, and quickly removing the tube, whereafter it is rinsed in water.

A bushing or ferrule is inserted in each end of the tube for a purpose which will'hereinafter appear. Each bushing 4 (Fig. 2) is of tubular form and preferably is of relatively greater thicktubes being shown as standing on end on a sup- I porting surface;

Fig. 11 is an enlarged fragmentary cross-sectional view taken along line Il--Il of Fig. but showing the condition of a. portion of the structure after the bonding operation, the thickness of the solder being somewhat exaggerated on the inside of the tube for clearness;

Fig. 12 is a front elevational view of one form of cartridge-type heat exchanger constructed in accordance with the invention;

Fig. 13 is an enlarged fragmentary view of a corner portion of the structure of Fig. 12, certain of the parts being broken away to show the interior construction;

Fig. 14 is a fragmentary side elevational view of a modified form of spacing strip and showing a plurality of tubes associated with the spacing strip;

Fig. 15 is a cross-sectional view taken along line I5|5 of Fig. 14;

Fig. 16 is a front elevational view of an automobile radiator and illustrative of a cartridge type heat exchanger core in which no spacing strips are employed between the rows'of tubes;

Fig. 1'7 is'a side elevational view of still another embodiment of the invention, wherein the tubes are secured in header plates; I

Fig. 18 is a fragmentary top plan view pf a portion of the structure shown in Fig. 1'2; apd

Fig. 19 is an enlarged "gmentary crosssectional view taken along li I 9-l9 of Fig. 18. In the following description and in the claims, various details will be identified by specific names for convenience, but they are intended to be as generic in their application as the art will permit. Like reference characters denote like Pfltts in the several figures of the drawings.

vided a suitable number of seamless tubes of the desired shape and size and formed from a suitable material. The tubes preferably are formed from copper but in certain cases, may be formed from other metal having the desired properties, such as good heat conductivity, sufficient duc- I or otherwise injure the tube.

accordance with the invention, there is pro- "ness than the wall of the tube. The bushing t corresponds in shape and diameter to the interior of the enlarged and of the tube and is adapted to fit snugly within the tube end, so as to'be in heat exchange contact therewith. Preferably, the bushing 4 is of such length that when in,-

' serted in the tube and flush with the end edge of the tube, it terminates short of the tapered shoulder l6 of the tube. Thus, when the bushing 4 is pressed into the tube, it will not be forced against the shoulder l6 and will not cut, collapse,

The end of the tube may have a cross-sectional shape other than round, in which case the bushing or ferrule is shaped to fit the tube. Fbr example, the tube end may be of hexagonal crosssection and have a hexagonal bushing therein;

the interior of the bushing may be hexagonal or circular.

In certain cases it may be found desirable to dispose the bushing or ferrule on the outside of the tube end instead of within the same; in which case the bushing, or ferrule, is formed to fit around the tube end. Where the bushing or ferrule is disposed on the outside of the tube and it is possible, in some cases, to eliminate the operation of expandingof the tube end, in which'case the bushing or ferrule is formed to fit snugly onto the unexpanded end of the tube. Generally, however, it is preferable to expand the tube and insert the bushing withinthe tube as described.

.A plurality of spacing members 6 (Fig. 4) or spacing strips are provided, which may take the form of strips, rods, bars or the like; Two opposite sides or edges of each spacing strip C are provided with a series of recesses I and interposed humps 8 formed in any one ofvarious ways. For example, the strip 6 may be given a generally corrugated shape by pressing a straight rod of metal between dies of suitable shape; and

may be slightly flattened as indicated, if desired.

Another form of spacing strip is illustratedin Figs. 13 and 14 whereinjthe strip 4| is formed between adjacent tubes. The bushed tubes 5 and spacing strips may be conveniently assembled by arranging two or more spacing strips 5 in spaced, parallel, relation ear/ eer and joining two or'more hushed tubes 5 thereto to form a generally frame-like assembly ll, as illustrated in r g. is. This'can be conveniently accomplished by providing any assembly frame 9, comprising side rails it and end rails ii. The and rails it are provided with iiccr portions it for receiving the spacing strips 6, adjacent shoulders it for positioning the spacing strips ii at the desired relative position and shoulders id for po= sitioning the bushed tubes 5. It will be understood that the core may be made in various other shapes than here disclosed, in'which case the frame 9 will beshaped as required.

Spacing strips are laid'on the floor portions 52 and hushed tubes 5 are disposed in correspending recesses l of the spacing strips, as illustratcd in Fig. 6, the tubes preferably being disposed in the endmost recesses l of the spacing scribed in connection with the bonding of the tubes.

For the purpose of holding the tubes and spacing strips during bonding, they are assembled in the general shape of the core to be produced and are held in position by a suitable clamp 2t. One such clamp is illustrated in Fig. 9 and comprises a frame 25 having presser bars 22 and 23 adjustably carried on adjacent sides or the. frame by screws which can be locked in position by loch nuts 25.

a corrugated side plate 29, of rigid construction and having its corrugations corresponding to the desired spacing of the tubes in the rows, is disposed in the clamp 2d. Individual hushed tubes are disposed in the grooves of the side plate is to form the first row of tubes. Thereafter, onset the assemblies ii is disposed in the frame with lower recesses ll of the spacing strips 6 receiving the tubes of the first row and additional individual tubes are disposed in the upper recesses l of the spacing" strips ii. A secand assembly ii is disposed on the second row of tubes ti with the recesses l! of the spacing strips receiving the tubes of the second row, and addltion l tubes are placed in the recesses of the second spacing strips, Additional assemblies and tubes are stacked in a iii-re manner until all of the tuhes nd strips which are to form the core are assembled, whereaiter a second side plate (not shown) is d posed n the top'row of tubes. .lhe ser 32 are then adjusted to to keep the temperature of the tubes below the annealing temperature oi the tube metal, during bonding. rules are insumcient, for this purpose, additional heat absorbing dissipating means is provided. For example, heat absorbing and. dissi patina" members may be inserted in some and preferably all of the tub-es.

Tillie additional heat dissipating members pref erably talre the form rods formed from metal of good heat absorbing capacity such as copper, iron, steel or the like and preferably are approximately the size or the interior of the tubes. in certain cases it is deslrableto employ rods of a metal such as iron or steel to which the bonding material will not readily adhere: thus there is less possibility that the rods will be bond All . around the tubes.

However, when the bushings or ierpreferably somewhat in excess or 1220" F.

ed to the tubes and hence can be readily removed therefrom when the bonding operation is com pleted. The rods preferably are of approximately the same diameter and slightly shorter than the inside of the tubes so that they will be in heat exchange contact with the tubes but can be readily removed after the tubes have been bonded. Preferably, the inside diameter of the bushings is approximately the same as the tube so that the bushings also are in heat exchange contact with the rod.

If desired, the additional heat dissipation may be effected without the use of rods inserted in the tubes. For example, a current of a gaseous cooling medium, preferably of a non-oxidizing na ture, may be passed through the space around the tubes. The cooling medium should flow in sufficient quantity to provide the desired cooling but should not be under such high pressure as to interfere with the bonding operation.

The tubes, strips and bushings are bonded together by applying bonding material over the end of the assembly within the frame, as indi cated in Fig. ll. The bonding material is ap plied so that when it solidifies it extends over the ends of the tubes and bushings and fills the spaces between the adjacent tubes and the space between the spacing strips, thus forming with the tubes, bushingsand strips a wall or header which provides a complete imperiorate seal Thus the tubes, bushings and spacing strips are firmly secured together to form a core structure having a completely sealed end which is entirely imperforate except for the passages provided by the tubes.

The bonding material (hereinafter called solder) is a fusible metallic material which has relatively high mechanical strength, which is suitably adherent to the members forming the heat exchanger, which is capable of withstanding relatively high temperatures, which is resistant to corrosion and deterioration, which will withstand vibration, shocl; and other destructive effects, and which is otherwise suitable for the present use. One bonding material which has been found suitable for practising the present invention is a so-called silver solder comprising around 45% by Weight of silver, 30% by weight of copper, and 25% by weight of zinc. It is also desirable to employ suitable flux, which may be any good commercially available flux adapted for use with solder of the composition employed.

The solder is applied by heating the same to a temperature above its fusing temperature and For this purpose it has been found desirable to em ploy an cry-acetylene flame.

The tubes, spacing strips and bushings at the other end or the core are soldered in a similar manner, the rods removed and the core is then removed from theclan'lp, Preferably, the side plates are not soldered to the tubes during the above-described soldering operation and hence,

can be separated. from the tubes. when the core is removed from the clamp.

after the core is assembled, above described, it preferably is cleaned to remove foreign inattensuch as carbon deposits, lilirt and the like. The core is cleaned by immersing it in a 5% sul= phuric acid solution, then rinsing it in cold water to remove the acid, this rinsing being effected by immersing the core in a cold water bath and agitating it .or flowing cold water past and through the core. The core is then immersed in boiling water a sufilcieiilrperiod to completely remove the acid from the niches or interstices and is dried immediately after removal from the hot water bath in a suitable manner as by placing it in a dry air oven.

The core 30 may be assembled with the side plates and with top and bottom tanks of any suitable construction by a soldering operation. The tanks may take any desired form; and for example, may be constructed similarly to the tanks 3| and 32 illustrated in Fig. 12, as generally similar. The tank 3| comprises a dished metal member having side walls 33, 33 and end walls 30, 34, all of which have outwardly extending flanges 35 formed by rebent edges of the tank. A corner piece 36 having a corrugated body and a flange 31 seated on the flange 35 is attached at each side of the tank.

The tanks 3|, 32, side plates 29 and corner pieces 36 are assembled by soldering, in a manner similar to that above described, along the edges of the side plates and the corner pieces. The core 30 is then slid into the space between the tanks 3|, 32 and side plates 29, with the tubes in the endmost rows fitting in the grooves in the side plates 29. The core is soldered to the tanks and side plates by applying solder to the adjacent portions of the core, tanks and side plates and the openings around the ends of the tubes are sealed by filling them with solder.

The core as described above is suitable for use in a heat exchanger of the type known as an "intercooler, wherein air is drawn past and around the tubes. The core is assembled with duct members (not shown) of. suitable construction which are attached to the core in a manner generally analogous to the attaching of the tanks to the core.

The invention is also well adapted for forming heat exchanger cores wherein the tubes are arranged in a close fitting assembly and no spacing members are employed. There is illustrated in Fig. 16 a radiator for an automobile wherein the core is constituted in this manner. The radiator 50 comprises a core top tank 56, bottom tank 51 and frame 55. The core 5| is constituted by a plurality of tubes 52 each of which is generally similar to the tube I, previously described and has therein bushings 53, generally similar to the bushings 4.

The core 5| is constructedby inserting the bushed tubes 52 in a clamp, such as the clamp in rows, the tubes of each row being disposed immediately upon the tubes of the next lower row and staggered, as illustrated. The assembled tubes are gripped by the clamp and solder is applied over the ends of the tubes and in the generally triangular shaped spaces between the adjacent tubes. The soldering operation preferably is generally similar to that above described. Prior to the soldering operation, rods (not shown) are inserted in the tubes in order to absorb the heat of soldering and prevent annealing of the tubes, or a cooling fluid is employed to maintain the tubes at the desired tem-' perature. Thus the tubes and bushings are securely and rigidly fastened together and an lmperforate seal is formed around the tubes. Side plates (not shown) which preferably are corrugated, are secured to the endmost tubes of the rows by soldering similar to the manner above described and the top tank 53 and bottom tank 51 are secured to the core by a similar soldering operation.

The present invention is also adapted for con- '20 illustrated in Fig. 9. The tubes are stacked aeeaeee structing heat exchanger@ wherein the tubes are assembled in header plates to form. the core. Referring now to Fig. 17 there is shown one novel embodiment of such a construction.

enlarged ends 68 which extend through suitably positioned openings 59 in the header plates. Inserted in the end of each tube is a bushing E0 which preferably is provided with a portion which projects out of the tube 51 and is provided with a flange 1| adapted to seat against the end edge of the tube. A quantity of solder I3 is disposed over the surface of the header plate 6| and against the end of the tube and the projecting portion of the bushing 10.

In order to provide suitable area of contact between the tube end and the solder, the tube may extend beyond the surface of the header plate. If desired, however, the end of the tube may be flush with the header plate and the openings 59 countersunk as indicated at- 12 to provide the desired extent of surface contact.

While the invention is applicable to heat exchangers of a large number of various sizes, it is especially well adapted to such devices as radiators, coolers and like equipment for internal combustion engines. The invention is especially valuable in connection with relatively small heat exchangers where the tubes have a very small wall thickness. In one specific illustrative, but not limiting example, the tubes and bushings had the following dimensions: tube length 9 inches, body diameter 0.230 inch, end diameter 0.260 inch, and wall thickness 0.006 inch; bushing, length 0.480 inch, diameter 0.246 inch, wall thickness 0.015 inch.

From the foregoing it will be seen that the present invention provides a method of forming radiator cores wherein thin walled tubes formed from metal, such as copper and the like, can be joined by the use of a fusible bonding material without unduly softening the tubes. The bushings or ferrules effectively prevent overheating and softening of the tubes and the additional heat removing means, where employed, further" prevents such undue heating.

The provision of the bushing or ferrule not only insures against overheating of the tube ends but also strengthens and reinforces the ends of the tubes. Thus, not only is the core reinforced but the individual tube ends are so reinforced that even if these portions of the tube should be softened, they will not be readily deformable.

What is claimed is:

1. A heat exchanger comprising a core including a plurality of thin-walled tubes arranged in rows to define substantially parallel passages for one fluid therethrough and having enlarged ends spacing their body portions apart to provide space for the passage of another fluid around the tubes, spacing strips interposed between at least certain of said rows adjacent the ends of the tubes, relatively thick-walled bushings in the ends of said tubes, and bonding material securing said tubes, spacing strips, and bushings tocorrugated side wall plates extending parallel to said spacing strips in two opposite sides of said core, and duct members disposed at two other 1 sides of said core and secured thereto with their thin walled copper tubes arranged successively in substantially parallel rows to define passages 'for one fluid therethrough, said tubes having .eniarged ends spacing the body portions apart I to provide space for the passage of another fluid around the tubes, relatively thick walled heat absorbing bushings disposed within said enlarged ends, means including silver solder connecting said enlarged ends, said silver solder securingsaid bushings in position and securing the enlarged ends of said tubesdirectly together in at least one direction, said enlarged ends, said bushings and said connecting means constituting built-up headers, enclosing walls surrounding said tubes and connected to said built-up headers, and duct members secured to said enclosing walls with their interiors in communication with the space between said tubes, said silver solder being fusible at a temperature above the annealing temperature of said tubes, said-bushings having sufllcient heat absorbing capacity to prevent annealing said tubes during the high temperature soldering operation, and strengthening said headers.

EMILE BLAIR, Ormmwrsa EMILIEN BLAIS; 

